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April 15, 2011: Cold Weather and the Hawks

April 15, 2011: Cold Weather and the Hawks

Credit: Dave Helzer

by Bob Sallinger

kgw.com

Posted on April 15, 2011 at 10:59 PM

Updated Wednesday, Oct 30 at 7:05 AM

Some folks have wondered about the impacts of the cold weather on the hawks. It has certainly been a cold and rainy spring!

Cold weather can disrupt nesting activities. However the hawks are equipped to deal with some pretty intense weather extremes. The parents have been dilligently incubating their eggs. The eggs are able to withstand some cooling as well---cooling tends to slow development as opposed to harming the eggs. Sometimes when the weather is particularly cold we see later hatching dates. The biggest threat to eggs is actually overheating rather than cooling. While egs can cool substantially and survive, an increase of just a few degrees above incubation temperatures can kill them.

Some folks on the facebook page have noticed that the parents seem more restless in recent days. The eggs may be getting close to hatching and the increasingly developed birds inside the eggs may be getting more active. Sounds like the facebook crowd has settled on the 16th as the most likely date for hatching. I am still putting my bets on later in the week.

For those interested in learning about some of our other urban raptors, I will be giving a talk this Tuesday night on urban peregrine falcons. Peregrines are the fastest animals on earth diving at speeds of over 200 miles per hour. Peregrine populations were wiped out by the pesticide DDT but have made an amazing comeback over the past several decades. Like the red-tails, peregrines are able to utilize manmade structures for nesting and we have a growing population of peregrines nesting on Portland area bridges. The talk is part of a series of OMSI Science Pubs. This one will be held at the Mission Theatre at 7:00 pm.

Peregrine Falcon on Interstate Bridge by Dave Helzer

Finally a bit of cool news: The Oregon Senate Environment Committee voted on Thursday to move Senate Bill 924 to the floor for a vote of the full senate. SB 924 strengthens penalties for poaching including for poaching involving illegal taking of birds of prey.

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